microblaze: Add KGDB support
Kgdb uses brki r16, 0x18 instruction to call low level _debug_exception function which save current state to pt_regs and call microblaze_kgdb_break function. _debug_exception should be called only from the kernel space. User space calling is not supported because user application debugging uses different handling. pt_regs_to_gdb_regs loads additional special registers which can't be changed * Enable KGDB in Kconfig * Remove ancient not-tested KGDB support * Remove ancient _debug_exception code from entry.S Only MMU KGDB support is supported. Signed-off-by: Michal Simek <monstr@monstr.eu> CC: Jason Wessel <jason.wessel@windriver.com> CC: John Williams <john.williams@petalogix.com> CC: Edgar E. Iglesias <edgar.iglesias@petalogix.com> CC: linux-kernel@vger.kernel.org Acked-by: Jason Wessel <jason.wessel@windriver.com>
This commit is contained in:
Michal Simek
parent
751f1605e0
commit
2d5973cb5a
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@ -14,6 +14,7 @@ config MICROBLAZE
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select USB_ARCH_HAS_EHCI
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select ARCH_WANT_OPTIONAL_GPIOLIB
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select HAVE_OPROFILE
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select HAVE_ARCH_KGDB
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select HAVE_DMA_ATTRS
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select HAVE_DMA_API_DEBUG
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select TRACING_SUPPORT
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@ -69,22 +69,6 @@ asmlinkage void full_exception(struct pt_regs *regs, unsigned int type,
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void die(const char *str, struct pt_regs *fp, long err);
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void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr);
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#if defined(CONFIG_KGDB)
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void (*debugger)(struct pt_regs *regs);
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int (*debugger_bpt)(struct pt_regs *regs);
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int (*debugger_sstep)(struct pt_regs *regs);
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int (*debugger_iabr_match)(struct pt_regs *regs);
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int (*debugger_dabr_match)(struct pt_regs *regs);
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void (*debugger_fault_handler)(struct pt_regs *regs);
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#else
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#define debugger(regs) do { } while (0)
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#define debugger_bpt(regs) 0
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#define debugger_sstep(regs) 0
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#define debugger_iabr_match(regs) 0
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#define debugger_dabr_match(regs) 0
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#define debugger_fault_handler ((void (*)(struct pt_regs *))0)
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#endif
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#endif /*__ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _ASM_MICROBLAZE_EXCEPTIONS_H */
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@ -0,0 +1,28 @@
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#ifdef __KERNEL__
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#ifndef __MICROBLAZE_KGDB_H__
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#define __MICROBLAZE_KGDB_H__
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#ifndef __ASSEMBLY__
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#define CACHE_FLUSH_IS_SAFE 1
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#define BUFMAX 2048
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/*
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* 32 32-bit general purpose registers (r0-r31)
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* 6 32-bit special registers (pc, msr, ear, esr, fsr, btr)
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* 12 32-bit PVR
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* 7 32-bit MMU Regs (redr, rpid, rzpr, rtlbx, rtlbsx, rtlblo, rtlbhi)
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* ------
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* 57 registers
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*/
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#define NUMREGBYTES (57 * 4)
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#define BREAK_INSTR_SIZE 4
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static inline void arch_kgdb_breakpoint(void)
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{
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__asm__ __volatile__("brki r16, 0x18;");
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}
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#endif /* __ASSEMBLY__ */
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#endif /* __MICROBLAZE_KGDB_H__ */
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#endif /* __KERNEL__ */
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@ -28,5 +28,6 @@ obj-$(CONFIG_MODULES) += microblaze_ksyms.o module.o
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obj-$(CONFIG_MMU) += misc.o
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obj-$(CONFIG_STACKTRACE) += stacktrace.o
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obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o mcount.o
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obj-$(CONFIG_KGDB) += kgdb.o
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obj-y += entry$(MMU).o
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@ -745,11 +745,8 @@ IRQ_return: /* MS: Make global symbol for debugging */
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nop
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/*
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* `Debug' trap
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* We enter dbtrap in "BIP" (breakpoint) mode.
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* So we exit the breakpoint mode with an 'rtbd' and proceed with the
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* original dbtrap.
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* however, wait to save state first
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* Debug trap for KGDB. Enter to _debug_exception by brki r16, 0x18
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* and call handling function with saved pt_regs
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*/
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C_ENTRY(_debug_exception):
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/* BIP bit is set on entry, no interrupts can occur */
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@ -759,18 +756,44 @@ C_ENTRY(_debug_exception):
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nop
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andi r1, r1, MSR_UMS
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bnei r1, 1f
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/* Kernel-mode state save. */
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/* MS: Kernel-mode state save - kgdb */
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lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
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tophys(r1,r1);
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addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
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/* BIP bit is set on entry, no interrupts can occur */
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addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE;
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SAVE_REGS;
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/* save all regs to pt_reg structure */
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swi r0, r1, PTO+PT_R0; /* R0 must be saved too */
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swi r14, r1, PTO+PT_R14 /* rewrite saved R14 value */
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swi r16, r1, PTO+PT_R16
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swi r16, r1, PTO+PT_PC; /* PC and r16 are the same */
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swi r17, r1, PTO+PT_R17
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/* save special purpose registers to pt_regs */
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mfs r11, rear;
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swi r11, r1, PTO+PT_EAR;
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mfs r11, resr;
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swi r11, r1, PTO+PT_ESR;
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mfs r11, rfsr;
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swi r11, r1, PTO+PT_FSR;
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swi r1, r1, PTO + PT_MODE;
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brid 2f;
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nop; /* Fill delay slot */
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1: /* User-mode state save. */
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lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
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/* stack pointer is in physical address at it is decrease
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* by STATE_SAVE_SIZE but we need to get correct R1 value */
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addik r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + STATE_SAVE_SIZE;
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swi r11, r1, PTO+PT_R1
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/* MS: r31 - current pointer isn't changed */
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tovirt(r1,r1)
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#ifdef CONFIG_KGDB
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addi r5, r1, PTO /* pass pt_reg address as the first arg */
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la r15, r0, dbtrap_call; /* return address */
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rtbd r0, microblaze_kgdb_break
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nop;
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#endif
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/* MS: Place handler for brki from kernel space if KGDB is OFF.
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* It is very unlikely that another brki instruction is called. */
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bri 0
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/* MS: User-mode state save - gdb */
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1: lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
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tophys(r1,r1);
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lwi r1, r1, TS_THREAD_INFO; /* get the thread info */
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addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */
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@ -781,36 +804,32 @@ C_ENTRY(_debug_exception):
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swi r17, r1, PTO+PT_R17;
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swi r16, r1, PTO+PT_R16;
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swi r16, r1, PTO+PT_PC; /* Save LP */
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swi r0, r1, PTO + PT_MODE; /* Was in user-mode. */
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lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
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swi r11, r1, PTO+PT_R1; /* Store user SP. */
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2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
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lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
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tovirt(r1,r1)
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set_vms;
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addik r5, r1, PTO;
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addik r15, r0, dbtrap_call;
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dbtrap_call: /* return point for kernel/user entry */
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dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
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rtbd r0, sw_exception
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nop
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set_bip; /* Ints masked for state restore*/
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/* MS: The first instruction for the second part of the gdb/kgdb */
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set_bip; /* Ints masked for state restore */
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lwi r11, r1, PTO + PT_MODE;
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bnei r11, 2f;
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/* MS: Return to user space - gdb */
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/* Get current task ptr into r11 */
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lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
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lwi r11, r11, TI_FLAGS; /* get flags in thread info */
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andi r11, r11, _TIF_NEED_RESCHED;
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beqi r11, 5f;
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/* Call the scheduler before returning from a syscall/trap. */
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/* Call the scheduler before returning from a syscall/trap. */
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bralid r15, schedule; /* Call scheduler */
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nop; /* delay slot */
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/* XXX Is PT_DTRACE handling needed here? */
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/* XXX m68knommu also checks TASK_STATE & TASK_COUNTER here. */
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/* Maybe handle a signal */
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5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
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@ -818,48 +837,37 @@ dbtrap_call: /* return point for kernel/user entry */
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andi r11, r11, _TIF_SIGPENDING;
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beqi r11, 1f; /* Signals to handle, handle them */
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/* Handle a signal return; Pending signals should be in r18. */
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/* Not all registers are saved by the normal trap/interrupt entry
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points (for instance, call-saved registers (because the normal
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C-compiler calling sequence in the kernel makes sure they're
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preserved), and call-clobbered registers in the case of
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traps), but signal handlers may want to examine or change the
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complete register state. Here we save anything not saved by
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the normal entry sequence, so that it may be safely restored
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(in a possibly modified form) after do_signal returns. */
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addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
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addi r7, r0, 0; /* Arg 3: int in_syscall */
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bralid r15, do_signal; /* Handle any signals */
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add r6, r0, r0; /* Arg 2: sigset_t *oldset */
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/* Finally, return to user state. */
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1:
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swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
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1: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
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VM_OFF;
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tophys(r1,r1);
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/* MS: Restore all regs */
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RESTORE_REGS
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lwi r17, r1, PTO+PT_R17;
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lwi r16, r1, PTO+PT_R16;
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addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
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addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space */
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lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer */
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DBTRAP_return_user: /* MS: Make global symbol for debugging */
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rtbd r16, 0; /* MS: Instructions to return from a debug trap */
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nop;
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lwi r1, r1, PT_R1 - PT_SIZE;
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/* Restore user stack pointer. */
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bri 6f;
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/* Return to kernel state. */
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/* MS: Return to kernel state - kgdb */
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2: VM_OFF;
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tophys(r1,r1);
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/* MS: Restore all regs */
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RESTORE_REGS
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addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
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lwi r14, r1, PTO+PT_R14;
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lwi r16, r1, PTO+PT_PC;
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lwi r17, r1, PTO+PT_R17;
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addik r1, r1, STATE_SAVE_SIZE; /* MS: Clean up stack space */
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tovirt(r1,r1);
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6:
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DBTRAP_return: /* Make global symbol for debugging */
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rtbd r16, 0; /* Instructions to return from an IRQ */
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DBTRAP_return_kernel: /* MS: Make global symbol for debugging */
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rtbd r16, 0; /* MS: Instructions to return from a debug trap */
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nop;
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@ -59,7 +59,6 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
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siginfo_t info;
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if (kernel_mode(regs)) {
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debugger(regs);
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die("Exception in kernel mode", regs, signr);
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}
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info.si_signo = signr;
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@ -0,0 +1,147 @@
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/*
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* Microblaze KGDB support
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/kgdb.h>
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#include <linux/kdebug.h>
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#include <linux/irq.h>
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#include <linux/io.h>
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#include <asm/cacheflush.h>
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#include <asm/asm-offsets.h>
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#include <asm/pvr.h>
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#define GDB_REG 0
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#define GDB_PC 32
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#define GDB_MSR 33
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#define GDB_EAR 34
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#define GDB_ESR 35
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#define GDB_FSR 36
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#define GDB_BTR 37
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#define GDB_PVR 38
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#define GDB_REDR 50
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#define GDB_RPID 51
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#define GDB_RZPR 52
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#define GDB_RTLBX 53
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#define GDB_RTLBSX 54 /* mfs can't read it */
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#define GDB_RTLBLO 55
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#define GDB_RTLBHI 56
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/* keep pvr separately because it is unchangeble */
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struct pvr_s pvr;
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void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
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{
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int i;
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unsigned long *pt_regb = (unsigned long *)regs;
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int temp;
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/* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */
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for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++)
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gdb_regs[i] = pt_regb[i];
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/* Branch target register can't be changed */
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__asm__ __volatile__ ("mfs %0, rbtr;" : "=r"(temp) : );
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gdb_regs[GDB_BTR] = temp;
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/* pvr part - we have 11 pvr regs */
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for (i = 0; i < sizeof(struct pvr_s)/4; i++)
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gdb_regs[GDB_PVR + i] = pvr.pvr[i];
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/* read special registers - can't be changed */
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__asm__ __volatile__ ("mfs %0, redr;" : "=r"(temp) : );
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gdb_regs[GDB_REDR] = temp;
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__asm__ __volatile__ ("mfs %0, rpid;" : "=r"(temp) : );
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gdb_regs[GDB_RPID] = temp;
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__asm__ __volatile__ ("mfs %0, rzpr;" : "=r"(temp) : );
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gdb_regs[GDB_RZPR] = temp;
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__asm__ __volatile__ ("mfs %0, rtlbx;" : "=r"(temp) : );
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gdb_regs[GDB_RTLBX] = temp;
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__asm__ __volatile__ ("mfs %0, rtlblo;" : "=r"(temp) : );
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gdb_regs[GDB_RTLBLO] = temp;
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__asm__ __volatile__ ("mfs %0, rtlbhi;" : "=r"(temp) : );
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gdb_regs[GDB_RTLBHI] = temp;
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}
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void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
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{
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int i;
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unsigned long *pt_regb = (unsigned long *)regs;
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/* pt_regs and gdb_regs have the same 37 values.
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* The rest of gdb_regs are unused and can't be changed.
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* r0 register value can't be changed too. */
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for (i = 1; i < (sizeof(struct pt_regs) / 4) - 1; i++)
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pt_regb[i] = gdb_regs[i];
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}
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void microblaze_kgdb_break(struct pt_regs *regs)
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{
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if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
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return 0;
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/* Jump over the first arch_kgdb_breakpoint which is barrier to
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* get kgdb work. The same solution is used for powerpc */
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if (*(u32 *) (regs->pc) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr))
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regs->pc += BREAK_INSTR_SIZE;
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}
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/* untested */
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void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
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{
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int i;
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unsigned long *pt_regb = (unsigned long *)(p->thread.regs);
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/* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */
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for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++)
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gdb_regs[i] = pt_regb[i];
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/* pvr part - we have 11 pvr regs */
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for (i = 0; i < sizeof(struct pvr_s)/4; i++)
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gdb_regs[GDB_PVR + i] = pvr.pvr[i];
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}
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void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
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{
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regs->pc = ip;
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}
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int kgdb_arch_handle_exception(int vector, int signo, int err_code,
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char *remcom_in_buffer, char *remcom_out_buffer,
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struct pt_regs *regs)
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{
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char *ptr;
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unsigned long address;
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int cpu = smp_processor_id();
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switch (remcom_in_buffer[0]) {
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case 'c':
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/* handle the optional parameter */
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ptr = &remcom_in_buffer[1];
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if (kgdb_hex2long(&ptr, &address))
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regs->pc = address;
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return 0;
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}
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return -1; /* this means that we do not want to exit from the handler */
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}
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int kgdb_arch_init(void)
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{
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get_pvr(&pvr); /* Fill PVR structure */
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return 0;
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}
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void kgdb_arch_exit(void)
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{
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/* Nothing to do */
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}
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/*
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* Global data
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*/
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struct kgdb_arch arch_kgdb_ops = {
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.gdb_bpt_instr = {0xba, 0x0c, 0x00, 0x18}, /* brki r16, 0x18 */
|
||||
};
|
||||
|
|
@ -37,10 +37,6 @@
|
|||
#include <linux/uaccess.h>
|
||||
#include <asm/exceptions.h>
|
||||
|
||||
#if defined(CONFIG_KGDB)
|
||||
int debugger_kernel_faults = 1;
|
||||
#endif
|
||||
|
||||
static unsigned long pte_misses; /* updated by do_page_fault() */
|
||||
static unsigned long pte_errors; /* updated by do_page_fault() */
|
||||
|
||||
|
|
@ -81,10 +77,6 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
|
|||
}
|
||||
|
||||
/* kernel has accessed a bad area */
|
||||
#if defined(CONFIG_KGDB)
|
||||
if (debugger_kernel_faults)
|
||||
debugger(regs);
|
||||
#endif
|
||||
die("kernel access of bad area", regs, sig);
|
||||
}
|
||||
|
||||
|
|
@ -115,13 +107,6 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
|
|||
if ((error_code & 0x13) == 0x13 || (error_code & 0x11) == 0x11)
|
||||
is_write = 0;
|
||||
|
||||
#if defined(CONFIG_KGDB)
|
||||
if (debugger_fault_handler && regs->trap == 0x300) {
|
||||
debugger_fault_handler(regs);
|
||||
return;
|
||||
}
|
||||
#endif /* CONFIG_KGDB */
|
||||
|
||||
if (unlikely(in_atomic() || !mm)) {
|
||||
if (kernel_mode(regs))
|
||||
goto bad_area_nosemaphore;
|
||||
|
|
|
|||
Loading…
Reference in New Issue